Let's say your application depends on two libraries A and B. And let's say that these 2 libraries depend on different versions of library C. In Maven if library C is not backward compatible, you're stuck. Only one version of library C can exist in the classpath and so one of your 2 libraries might fail. However, in node, library A and B use their corresponding versions of library C. There are no conflicts.

This is amazing. I'm actually surprised NPM is one of the few that gets this right. I guess we are still in the early days of Software engineering.

No conflicts, but a tradeoff of loading two versions of library C. I assume at some point, the cost of multiple versions of everything (in terms of memory usage, for example) becomes an issue?

That's the tradeoff, with the crux being that adding more memory for a bit of JIT-compiled bytecode is preferable to having an app that just won't work.

There is something to be said for requiring developers to make things work right rather than work around their screwups, however.